1. Field of the Invention
This invention relates broadly to surgical systems and methods. More particularly, this invention relates to a system and method for fracture fixation for a dorsal distal radius fracture.
2. State of the Art
Fractures of the wrist are difficult to align and treat. Alignment and fixation are typically performed by one of several methods: casting, external fixation, interosseous wiring, and plating. Casting is noninvasive, but may not be able to maintain alignment of the fracture where many bone fragments exist. Therefore, as an alternative, external fixators may be used. External fixators utilize a method known as ligamentotaxis, which provides distraction forces across the joint and permits the fracture to be aligned based upon the tension placed on the surrounding ligaments. However, while external fixators can maintain the position of the wrist, it may nevertheless be difficult in certain fractures to first provide the bones in proper alignment. In addition, external fixators are often not suitable for fractures resulting in multiple bone fragments. In addition, external fixation is associated with reflex sympathetic dystrophy, stiffness, and pin complications. Moreover, with some fractures, movement of the wrist is an essential part of rehabilitation, and this movement is prevented by external fixation. Interosseous wiring is an invasive procedure whereby screws are positioned into the various fragments and the screws are then wired together as bracing. This is a difficult and time consuming procedure. Moreover, unless the bracing is quite complex, the fracture may not be properly stabilized.
Volar wrist fractures (Colles"" fractures) have been treated with a volar plate and screw system. The volar plate is generally a T-shaped plate having a head portion and a body portion. The body portion has holes along its length and the head portion has holes at its distal end. The holes are for receiving self-tapping bone screws therethrough. In use, the bone fragments of the volar wrist fracture are aligned and the body portion of the plate is screwed to an integral portion of the radius proximal of the fracture. Screws are then provided through the holes in the head portion to define a stabilizing framework about the fractured bone fragments heal.
Dorsal wrist fractures have also been treated with a plate, but the plate is attached to the dorsal side of the radius. Referring to prior art FIG. 1, dorsal fixation has previously used a relatively thin plate 10 secured to the dorsal side of the radius 12. Like the volar plate, the dorsal plate 10 has a body portion 14 and a head portion 16. Holes 18 are provided in the both the body and head portions, and screws 20 extend therethrough into the radius 12 to compress the plate 10 against the bone and stabilize the fracture. The plate design, in terms of strength and support, has not been critical, as the forces on the dorsal plate from the tendons and bending forces are not substantially large. In fact, there is substantially no bending load on a dorsal plate. However, use of the dorsal plate commonly results in extensor tendon problems, as the extensor tendons run close to the bone surface and are irritated by the plate. In addition, it is common in distal radius fractures for one or more fragments, e.g., the radial styloid fragment, the volar dipunch fragment, and/or the dorsal dipunch fragment, to become loosened or detached from the bone system. It is necessary to stabilize these fragment to prevent further movement relative to the desired stabilizing arrangement and prevention of desired healing. Yet, stabilization of this bone with a dorsal plate is impractical, as the fragments are located on the opposite side of the bone from the dorsal plate. As such, a new dorsal wrist fracture fixation system is desired.
It is therefore an object of the invention to provide a fracture fixation system for a dorsal wrist fracture.
It is another object of the invention to provide dorsal fracture fixation in a manner which does not cause extensor tendon irritation.
It is also an object of the invention to provide a dorsal fracture fixation system which stabilizes distal radius bone fragments.
It is a further object of the invention to provide a dorsal fracture fixation system which provides stability and support to the fracture to overcome the forces from the tendons and rotational forces at the fracture.
In accord with these objects, which will be discussed in detail below, a dorsal fracture is treated from the volar side by using a fixation plate. The plate is generally a T-shaped plate defining an elongate body portion, a head portion transverse to the body portion, and a neck portion therebetween. The neck portion defines a fixed angle between the head and body portions. The plate also includes a first side intended to contact the bone, and a second side opposite the first side. The plate is substantially thick and rigid, and made of a high strength material such as titanium to resist the high bending loads to which a volar plate is subject in order to stabilize a dorsal fracture.
The head portion includes a plurality of threaded peg holes for receiving pegs therethrough. The center of the peg holes are preferably arranged along a line, with the axis of each peg hole preferably being in an oblique orientation relative to the axes of the other peg holes such that pegs therethrough are obliquely oriented relative to each other. According to one preferred aspect of the invention, at least half of the head portion extends on the distal side of the line defining a buttress on which to support bone fragments. The body portion includes a plurality of screw holes for the extension of the bone screws therethrough.
According to another preferred aspect of the invention, one or more channels extend in the first side of the head portion of the plate, preferably substantially parallel to the body portion. One or more wires are partially provided within the channels, and extend distally from the head portion of the plate to provide additional support for one or more bone fragments. The wires includes a distal means for anchoring to one or more bone fragments, and are coupled to their proximal ends of the plate.
According to another embodiment of the volar plate, the buttress comprises a plurality of tines, which may be bent to access and support distal articular fragments of a fracture.
In use, the plate is positioned with its first side against the volar side of the radius and bone screws are inserted through the bone screw holes into the radius to secure the volar plate to the radius. The bone fragments of the dorsal fracture are then aligned. A drill drills holes through the peg holes and into the bone fragments. The pegs are then inserted through the peg holes and into the holes in the bone, and threadably locked in position, with the head portion buttress supporting the bone fragments. The optional wires and tines also assist in bone fragment support. The structure of the plate, as well as the ability of fragment to slide along the bone pegs permits the plate to withstand the forces on the plate and provide a stabilizing structure which facilitates healing.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.